Two-way radios, or walkie-talkies, are portable radio transceivers that do not require any network connection for sound or voice exchanges. Two-way radio is more suitable for frequent contacts between fixed partners because no connection or exchange charges are generated. The device was first developed for the military but later became widely used. The main features of two-way radios include: half-duplex mode (you can only accept or send voice exchanges at a particular time) and you need to press a button before the contents can be transferred. Most two-way radios look like a typical hand-held mobile phone with an antenna on the top.
Traditional two-way radios use antenna for transmitting and receiving radio signals. Although it does not require network support or generate charges, two-way radios still have the following disadvantages: the communication is significantly limited by distance; the devices must be purchased and sometimes supplemental transmitting devices need to be purchased separately, making the overall cost very high; the two-way radios may only communicate between one another, without any connection to regular mobile phones and other devices; most countries heavily regulate radio frequencies—using public frequencies jeopardizes privacy, but using other frequencies needs government approval.
In order to solve the above problems of the conventional two-way radio, some application programs have been developed for mobile phones. After installing one of the application programs, users may communicate with one another in a similar manner as a conventional two-way radio, though the communication is based on digital network technologies such as WiFi, GRPS, and 3G. Such an approach eliminates disadvantages such as distance limitations, purchasing of separate intercom equipments, lack of privacy protection, and government regulations of frequencies. However, this approach also requires the users to download, install, and get familiar with the application software, resulting in complex operation and causing inconvenience.
Accordingly, it is necessary and desirable to provide a new technology, so as to resolve the technical problem and improve the above-mentioned approach.